1. Technical Field
The present invention is directed to aircraft landing gear, and more particularly to an improved apparatus for pre-rotating aircraft wheels prior to landing, i.e., rotating the wheels so that at touchdown the tangential speed of the wheels closely matches the speed of the aircraft thereby reducing wear on the tires and simultaneously reducing torque on the landing gear typically due to unequal wheel speed at touchdown.
2. The Prior Art
In a typical commercial airliner, a large degree of wear and tear is experienced by the landing gear tires during each landing. In general, the tires must be inspected for excessive wear and tear after about 350 landings. The inspections are time consuming and expensive for the airlines. Moreover, when excessive wear and tear is evident, the tires must be recapped or replaced, increasing the expense.
U.S. Pat. No. 4,385,739, to Soderberg discloses a system for pre-rotating the wheels of an aircraft. A mechanical housing is affixed at the center of the wheels and contains a plurality of blades symmetrically positioned about a central axis. A nozzle is disposed so as to direct a stream of air at the blades prior to landing, thereby causing rotational movement of the housing and wheel.
U.S. Pat. No. 4,615,498 to Ochiai discloses a wheel and tire for an aircraft which includes a plurality of equiangularly spaced wind receiving ledges attached to the wheel. The ledges are disposed such that as the wheel moves through the air, the contact of the wind on the ledges causes the wheel and tire to be pre-rotated before the airplane lands.
U.S. Pat. No. 3,866,860 to Opitz, Sr. discloses a housing that covers more than 50% of the upper part of an aircraft wheel. The housing has a frontal air shroud with a center web portion spanning the width of the tire, and having flanges on either side. The shroud compresses the air and directs the passing air to the exposed lower half of the wheel. The air stream exerts a torque on the wheel, causing it to spin in the direction in which the airplane is travelling.
U.S. Pat. No. 4,061,294 to Hawkins discloses an aircraft wheel rotator including a plow like air collector which directs the passing air towards the spokes of the wheel, causing the wheel to rotate.